public class Solution extends BinaryTree {
    public TreeNode lowestCommonAncestor(TreeNode root,TreeNode p,TreeNode q) {
        if(root == null) {
            return null;
        }
        if(root == p || root == q) {
            return root;
        }
        TreeNode left = lowestCommonAncestor(root.left,p,q);
        TreeNode right = lowestCommonAncestor(root.right,p,q);
        if(left != null && right !=null) {
            return root;
        }else if(left != null) {
            return left;
        } else  {
            return right;
        }
    }
}
